Blender 2.49b crashes when right-clicking to select an object
Runnig such an old version of Blender on a modern version of windows can lead to incompatibilities such as you are experiencing - the old versions were obviously developed way before Windows 10 was even imagined and there are all kinds of reasons why newer Windows could expose a bug that’s been dormant and undiscovered in the old Blender code.

Probably the best way forward is to run against an older version of the operating system that doesn’t experience the problem. If you don’t have the physical hardware to run such a system you can run it as a ‘virtual’ computer using VM tools such as VirtualBox. I’ve had great success running older versions of Blender on VirtualBox running Linux (which is free to install if you can’t get Windows XP) - so I currently have a Windows 10 laptop running Blender 2.79.6 and Blender 2.8 and use a Linux VM (in VirtualBox) to run earlier versions.